The present invention relates to surface planers having variable speed feed rollers and methods of manufacture thereof.
Surface planers are most commonly provided with a pair of feed rollers; one on the in feed and one on the out feed side of the rotary cutter head for moving a wooden board to be planed relative to the cutter head at a fixed speed. The only adjustment an operator typically has for taking a light or heavy cut is the position the cutter head is spaced from the support platen which determines the depth of cut. When it is desired to take a light cut, a very small incremental adjustment is made between the in planing passes. When it is desired to make a rough cut, a relatively large in depth adjustment is made between planing passes so that the material is removed more quickly.
There have been limited efforts in the past to infinitely vary the speed of the board to be planed relative to the cutter head. U.S. Pat. No. 3,718,168 assigned to Rockwell Manufacturing Company, discloses a belt drive feed roller where the drive ratio can be varied by the operator using a variable diameter pulley system. U.S. Pat. No. 4,440,204 assigned to Shopsmith, Inc., discloses a planer attachment for a multi-purpose tool which is provided with a separate variable speed drive motor for advancing the feed rollers. The speed of the feed rollers can be varied by the operator dependent upon the characteristics of the board to be planed.
The variable feed speed planers prior art tend to be bulky and expensive. The object of the present invention is to make a simple robust low cost multi-speed in feed roller drive system which can be adapted to the existing single speed planers with minimal modification.
Accordingly, a surface planer of the present invention is provided with a motor having an output member, a rotary cutting head operatively connected to the motor output member and at least one feed roller positioned parallel to and adjacent the rotary cutter head for moving a wood board to be planed relative to the rotary cutting head. A multi-stage transmission is interposed between the motor and the feed roller. The multi-stage transmission has an input connected to the motor and an output drivingly connected to a feed roller. The multi-stage transmission has a dual speed stage provided with an operator""s actuated speed selector element which when shift between two positions, changes the final drive ratio resulting in a change in speed of the feed rollers.
In the preferred surface planer illustrated, the dual speed stage is provided by a planetary gear set which is the final stage and is remotely located from the remaining stages of the multi-stage transmission.
Also disclosed is a method of manufacturing a family of surface planers with differing in feed operating characteristics while maintaining part commonality. A basic surface planer subassembly is provided in a motor rotary cutter, a pair of feed rollers, frame including a platen, and a first gearbox having a multi-stage gear reduction including an input connected to the motor output member and a first gearbox output member. Wherein a low price single speed surface planer is fabricated by installing a fixed diameter circular drive element on the first gear box output member which is operatively coupled to the corresponding fixed diameter circular drive element on the feed roller by a flexible tensile member and trained thereabout. Alternatively a higher priced dual in feed speed surface planer can be fabricated by installing a second gearbox on the first gearbox output shaft, the second gearbox having a circular drive element forming a second gearbox output member operatively coupled to the fixed drive element on the feed roller by a flexible tensile member. The second gearbox is further provided with a speed selector element shiftable between a high and low position for selectively changing the gearbox drive ratio and the resulting rotational speed of the feed roller in order to enable the operator to vary the speed that a wooden board is fed post the rotary cutter head.